In the emerging Internet era, communications between personal computers (PCs) is becoming routine. While desk and laptop PCs offer telecommunications access to a variety of different server networks, these devices are costly, large, bulky, and require AC power or large rechargeable batteries. PC communication networks are generally one "big party line" that allow eaves-dropping and they are therefore vulnerable to thieves. Ease-dropping enables clever thieves to make clones of legal devices that may be used to access confidential financial accounts and private information. For most business activities public networks need clone detection systems that are infallible. Facsimile communications between PCs are even less secure, and they suffer from other disadvantages in that communication is commonly restricted to textual and/or graphic materials and do not commonly allow voice or audio content particularly if operated at low power settings. Likewise, telephone conversation commonly involves voice without textual or graphic support.
PC's with CD-ROMs offer read-only multimedia capability, but generally the information is not updated on a real-time basis and the content rapidly becomes obsolete. Desktop or laptop PCs are still quite expensive and expensive when compared with the cost and apparent simplicity of a telephone. The standard 101 keys on a keyboard require that the operator know how to type. The PC also requires familiarity with the general features of the computer operating system and user software (including telecommunications software.) In large organizations software upgrades require a significant investment in training. While some in our population are becoming more computer literate, many are not. In use as telecommunications devices, PCs have the following additional disadvantages: namely, being limited to keystrokes and a mouse for input; requiring AC power or rechargeable batteries; and, being bulky and large so that they are not easily carried in a coat pocket or handbag.
U.S. Pat. No. 4,961,220, "Power Management in a Microprocessor-Controlled Battery-Powered Telephone Device", issued Oct. 2, 1990, in the name of Michael L. Tentler et al. and assigned to Spectrum Concepts, Inc., describes a telephone terminal device that is partially powered by a telephone line but using a battery to supply current when telephone line power is inadequate. The terminal includes a microprocessor that is on at all times, and that draws significant current even when the terminal is inactive. Also, the disclosure does not appear to include a means for voice or data communications.
In everyday personal and business life there are many times when it would be highly desirable to have a low power, inexpensive, relatively lightweight, handheld unit that would have the `touch` and `feel` of a telephone (or a cordless or cellular telephone), and could transparently establish interactive voice and data telecommunications with a host server in a rapid real-time manner so that the unit transparently acquired the attributes of the large powerful computer.